JP2007266937A - Guidance voice mixing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a guidance voice mixing apparatus capable of allowing a listener to hear a mixed sound comprising a reproduction sound by an audio signal and guidance voice by a guidance voice signal and allowing the listener to hear the mixed sound in a way of clearly hearing the guidance voice and hearing the reproduction sound without a sense of incongruity. <P>SOLUTION: The guidance voice mixing apparatus includes: a low frequency component detection section 40 for detecting a level of a prescribed low frequency component of an audio signal Sa, a listening environment detection section 50 for detecting a listening environment, an audio signal processing section 22 cuts off and attenuates the prescribed low frequency component of the audio signal Sa on the basis of a detection result LV by the low frequency component detection section 40 and a detection result RC of the listening environment detection section 50 to produce a corrected audio signal Sac for reducing a masking effect applied to the guidance voice, and a guidance signal processing section 30 applies compression processing to the guidance voice signal Sz to produce a correction guidance voice signal Szc for reducing the masking effect from the reproduction sound by the audio signal. Further, a mixing section 80 mixes the correction audio signal Sac and the correction guidance voice signal Szc and supplies the mixed signal to a speaker 400, from which the mixed signal is reproduced. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a guidance voice mixing device that mixes a guidance voice signal of an in-vehicle navigation device or the like with, for example, a reproduced music signal of an in-vehicle audio device.

  2. Description of the Related Art In recent years, in-vehicle navigation devices and in-vehicle audio devices mounted on vehicles include reproduced music signals (hereinafter referred to as “audio signals”) reproduced by the in-vehicle audio devices, and guidance voices generated by the in-vehicle navigation devices. An apparatus is provided for supplying a signal to a speaker and reproducing reproduced music and guidance voice.

  If the reproduced music and the guidance voice are reproduced simultaneously with the speaker, the guidance voice is masked by the reproduced music or the like due to the masking effect which is a human auditory characteristic. Since it becomes difficult to hear, the device has been devised to make it easy to hear the guidance voice (see Patent Document 1 and Patent Document 2).

  In other words, for example, in the noise of a running train, passengers talk loudly, but still often do not communicate well. In such a case, it is said that the voice is masked by noise, and the masking effect is a phenomenon in which one stimulus (speaking voice) is concealed by the other stimulus (noise) and the listening ability of the stimulus (speaking voice) to be listened to decreases. Say. As in such a case, if the reproduced music or the like and the guidance voice are reproduced simultaneously with the speaker, the reproduced music masks the guidance voice and it becomes difficult to hear the guidance voice, so that the guidance voice can be easily heard. Have been devised.

  In the invention described in Patent Document 1, an audio signal and a guidance voice signal are mixed (mixed), and the mixed signal is supplied to a vehicle-mounted speaker to output reproduced sound. Furthermore, based on the own vehicle position information detected by the own vehicle position detecting means, it is configured to automatically determine whether or not the vehicle approaches a specific intersection and voice guidance for route guidance should be performed. When it is determined that the voice guidance should be performed, the navigation controller controls the in-vehicle audio device to attenuate the volume of the music being played or to stop the playback operation, thereby making it easy to hear the guidance voice. When the vehicle passes and there is no need for voice guidance, the volume of music being played is restored or the playback operation is resumed.

  In the invention described in Patent Document 2, the guidance voice signal and the audio signal are switched to the driver seat side speaker, the passenger seat side speaker, and the rear seat side speaker mounted on the vehicle, thereby providing guidance to the driver. The sound is controlled so that it is easy to hear. In other words, when there is no need for voice guidance, audio signals are supplied to all in-vehicle speakers, making it easier for the driver and passengers to hear the reproduced music. When voice guidance is given, guidance is given to the driver side speaker. By supplying only audio signals and supplying only audio signals to the passenger side and rear seat side speakers, it is easy for the driver to hear the guidance voice and the passengers can listen to the reproduced music. .

JP-A-8-105753 JP 2000-65592 A

  By the way, in the invention described in Patent Document 1, when audio guidance and guidance voice signals are mixed and voice guidance is performed, the volume of reproduced music or the like with respect to the guidance voice is simply reduced by reducing the level of the audio signal to zero. When the voice guidance is completed after the volume is reduced or reduced to zero, the level of the audio signal is restored to restore the volume of the reproduced music or the like. However, there is a problem that if the volume of the reproduced music is reduced or reduced to zero or restored each time the voice guidance is performed, the driver or passengers who are listening to the reproduced music feel uncomfortable.

  In the invention described in Patent Document 2, when not performing voice guidance, reproduced music or the like is output from all speakers including the driver's seat speaker, and when performing voice guidance, only guidance voice is output from the driver's seat speaker. Only reproduced music or the like is output from the speaker. However, if the playback music etc. being output from the driver's seat speaker is shut off and restored every time voice guidance is performed in this way, the sound image of the playback music etc. that has been localized on the driver's seat speaker moves to the other speaker side. In addition, since it is localized in the driver's seat speaker, there is a problem that the driver who is listening to the reproduced music feels uncomfortable.

  The present invention has been made in view of the above-described problems of the prior art. For example, the influence of the masking effect due to the reproduced music is reduced to clarify the guidance voice, and the reproduced music is listened to. It is an object of the present invention to provide a guidance voice mixing device that can prevent a listener from feeling uncomfortable.

  The invention according to claim 1 is a guide voice mixing device that mixes a guide voice signal and an audio signal and reproduces the mixed signal by a speaker, and detects a level of a predetermined low frequency component of the audio signal. A low frequency component detection means, and a cutoff frequency is adjusted based on a detection result of the low frequency component detection means to cut the low frequency component of the audio signal, and the level of the audio signal from which the low frequency component is cut is adjusted. Audio signal processing means for generating a corrected audio signal by attenuating according to the detection result of the low-frequency component detecting means, and mixing means for mixing the guidance voice signal and the corrected audio signal. And

  According to an eighth aspect of the present invention, there is provided a guidance voice mixing method for mixing a guidance voice signal and an audio signal and reproducing the mixed signal by a speaker, and detecting a level of a predetermined low frequency component of the audio signal. A low frequency component detection step and an audio signal obtained by adjusting the cutoff frequency based on the detection result detected in the low frequency component detection step to cut the low frequency component of the audio signal and cutting the low frequency component An audio signal processing step of generating a corrected audio signal by attenuating the level of the low frequency component in accordance with the detection result detected in the low-frequency component detection step, a mixing step of mixing the guidance voice signal and the corrected audio signal, It is characterized by comprising.

  The best mode for carrying out the invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing the configuration of the guidance voice mixing apparatus of the present embodiment, and FIG. 2 is a characteristic diagram for explaining the function of the guidance voice mixing apparatus.

  In FIG. 1, the guidance voice mixing device 10 includes an audio signal processing unit 20 having a frequency correction unit 21 and a gain correction unit 22, a guidance voice signal processing unit 30 having a frequency correction unit 31 and a gain correction unit 32, An audio sound signal Sa output from the audio device 100 including a receiver, a DVD player, and the like is provided in the navigation device, and includes a region component detection unit 40, a listening environment detection unit 50, amplifiers 60 and 70, and a mixing unit 80. The guidance voice signal Sz output from the guidance voice signal generator 200 and the sensor signal Si output from the sensor unit 300 such as a vehicle speed sensor installed in the vehicle are input, and these signals Sa, Sz, Mixing is performed by mixing (mixing) the corrected audio sound signal and the guidance voice after performing a predetermined correction process based on Si Supplied to the in-vehicle speaker 400 generates a No. Sm.

  Note that the guidance voice mixing device 10 shown in FIG. 1 is not provided only for a specific speaker such as a driver-side speaker or a passenger-side speaker mounted on a vehicle, but for each speaker. Provided.

  The low frequency component detection unit 40 is set to a cut-off frequency fc (for example, 300 Hz) that is lower than the frequency band (for example, 300 Hz to 3.4 kHz) of the guidance voice that is reproduced based on the guidance voice signal Sz. The low frequency component of the audio signal Sa is extracted by a low pass filter or a band pass filter whose pass band is a frequency band lower than the cut-off frequency fc, and the level of the low frequency component is detected. Then, a level detection signal LV indicating the level of the detected low frequency component is supplied to the frequency correction unit 21 and the gain correction units 22 and 32.

  Based on the sensor signal Si from the sensor unit 300, the listening environment detection unit 50 detects the listening environment in the vehicle interior when the listener listens to the sound output from the speaker 400, and detects the environment. The signal RC is supplied to the frequency correction units 21 and 31 and the gain correction units 22 and 32. That is, based on the sensor signal Si indicating the vehicle speed output from the vehicle speed sensor, the noise level in the vehicle interior with respect to the vehicle speed is estimated by a predetermined algorithm, and the degree to which the noise level causes a masking effect on the guidance voice is determined. Evaluation is performed at a frequency such as “large”, “medium”, and “small”, and an environment detection signal RC indicating the evaluated frequency is generated and output.

  Further, as an example, the case where the environment detection signal RC is generated based on the sensor signal Si output from the vehicle speed sensor has been described. However, the sensor signal Si from the sensor that detects whether or not the in-vehicle headlight is turned on is used. When the headlight is turned off, it is estimated that it is running in the daytime when it is difficult to hear the guidance voice, and the degree of causing the masking effect is evaluated as “large”, and when the headlight is turned on Estimating that the guidance voice is traveling at night when it is easy to hear, evaluate that the degree of causing the masking effect is “small”, and generate and output the environment detection signal RC indicating the evaluation result.

  Further, the vehicle interior estimated based on the noise level intruding into the vehicle interior estimated based on the sensor signal Si from the sensor for detecting the opening / closing amount of the window and the sensor signal Si from the sensor for detecting the operation speed of the in-vehicle wiper. The degree of the masking effect is evaluated based on the noise level entering the vehicle and the noise level in the passenger compartment estimated based on the sensor signal Si from the sensor that detects the air volume of the air conditioner. Is generated and output.

  Further, the number of passengers is judged based on the sensor signal Si from the sensor for detecting the number of seat belts attached. When the number of passengers is large, the degree of causing the masking effect is evaluated as “large”, and when the number of passengers is small. The degree of causing the masking effect is evaluated as “small”, and the environment detection signal RC indicating the evaluation result is generated and output.

  Also, an adjustment amount of the volume adjustment volume set in the audio device 100 is input as the sensor signal Si, the degree of causing the masking effect is evaluated according to the set volume, and the environment detection indicating the evaluation result A signal RC is generated and output.

  As described above, the listening environment detection unit 50 outputs the listening environment that is difficult to hear due to the influence of the masking effect when the guidance voice is output from the speaker 400 to the center signal Si from various sensors mounted on the vehicle. Based on the evaluation, an environment detection signal RC indicating the evaluation result is generated and output.

  The design method of the predetermined algorithm for performing the above-described evaluation will not be described in detail because it exists in accordance with the design specifications, but it is designed by performing experiments and simulations so that a reliable evaluation result can be obtained. The listening environment detection unit 50 is formed by a lookup table or the like that outputs an environment detection signal RC indicating a reliable evaluation result for a plurality of sensor signals Si from various sensors.

  A frequency correction unit (hereinafter referred to as “first frequency correction unit”) 21 included in the audio signal processing unit 20 automatically sets the cutoff frequency fa based on the level detection signal LV and the environment detection signal RC. It is formed by a high-pass filter (variable high-pass filter) that changes.

  Here, the audio signal processing unit 20 automatically adjusts the cutoff frequency fa based on the principle described below.

  First, FIG. 2A is an explanatory diagram schematically showing a masking effect in human hearing. When a masking sound (A sound) has a frequency fo (for example, 100 Hz), the masking effect by the A sound is shown. The relationship of the sound of the frequency (B sound) is shown as a masking curve C. Further, the horizontal axis represents frequency, and the vertical axis represents sensory level. Such a masking curve C is known by various studies on human hearing (Wegel, R.L. and Lane, C.E .: Phys. Rev., 23, 266-285 (1924)).

  In FIG. 2A, when the B sound exists within the frequency range of the masking curve C and the level is lower than the masking curve C (when B1, B2, etc.), the B sound cannot be heard at all. That is, when the frequency and level of the B sound are within the range (X) (Y) of the masking curve C, the B sound is completely masked by the A sound and cannot be heard.

  On the other hand, if the B sound exists outside the frequency range of the masking curve C (when B3 or the like), the B sound can be heard without being masked by the A sound.

  Here, as is apparent from the masking curve C, the masking effect of the A sound relative to the B sound may be narrow in the frequency range (X) lower than the frequency fo and wide in the frequency range (Y) higher than the frequency fo. I understand.

  When the tendency of masking in human hearing is analyzed, the following tendencies (a) and (b) are obtained. (a) Low-frequency sounds are easy to mask high-frequency sounds, and high-frequency sounds are difficult to mask low-frequency sounds. (b) When the level of the sound to be masked (A sound) increases, the masking frequency range (frequency range for masking the B sound) widens, and the masking amount of the A sound for the B sound increases.

  Using the masking tendencies (a) and (b) described above, the first frequency correction unit 21 automatically adjusts the cutoff frequency fa.

  That is, from the above tendency (a), the guidance voice is easily masked by low-frequency components such as reproduced music reproduced based on the audio signal Sa. Therefore, the low-frequency components of the audio signal Sa (frequency band of the guidance voice signal Sz) The cut-off frequency fa is automatically adjusted according to the level detection signal LV indicating the level of the lower frequency component). More specifically, as the value of the level detection signal LV increases as shown in the characteristic diagram of FIG. The low frequency component of the audio signal Sa is removed by biasing the cut-off frequency fa to the high frequency side within a range equal to or lower than the frequency band of the audio signal Sz.

  Furthermore, the first frequency correction unit 21 of the present embodiment is based not only on the masking effect due to low frequency components such as reproduced music reproduced based on the audio signal Sa, but also on the frequency indicated by the environment detection signal RC described above. As shown in FIG. 2B, the cut-off frequency fa is adjusted.

  Next, a gain correction unit (hereinafter referred to as “first gain correction unit”) 22 included in the audio signal processing unit 20 automatically sets the attenuation rate based on the level detection signal LV and the environment detection signal RC. It adjusts the level of an audio signal that is formed by an electronic attenuator that changes the frequency and an amplifier that automatically changes the amplification factor and from which the low frequency component output from the first frequency correction unit 21 is cut. That is, from the above-described masking tendency (b), the masking amount for the guidance voice increases as the volume of the reproduced music or the like reproduced based on the audio signal increases, so as shown in the characteristic diagram of FIG. In addition, as the value of the level detection signal LV increases, the audio signal from the first frequency correction unit 21 is attenuated (gain is reduced), thereby reducing the masking amount.

  Furthermore, as shown in FIG. 2C, the first gain correction unit 22 of the present embodiment is based on the frequency indicated by the above-described environment detection signal RC as well as the level detection signal LV. The amount of masking is reduced by attenuating the audio signal from the frequency correction unit 21 (lowering the gain).

  Then, the corrected audio signal Sac output from the first gain correction unit 22 is amplified by the level adjustment amplifier 60 fixed at a predetermined amplification factor and supplied to the mixing unit 80.

  Next, a frequency correction unit (hereinafter referred to as a “second frequency correction unit”) 31 included in the guidance voice signal processing unit 30 is a frequency at which the guidance voice signal Sz can be heard as a clearer guidance voice from the viewpoint of hearing. It is formed with a band pass filter or the like set in a predetermined pass frequency range that allows the component to pass therethrough.

  A gain correction unit (hereinafter referred to as a “second gain correction unit”) 32 included in the guidance voice signal processing unit 30 is formed to include a compression processing unit and the like, and has the characteristics shown in FIG. As shown in the figure, based on the level detection signal LV and the environment detection signal RC, a compression process is performed on the guidance voice signal from the second frequency correction unit 31, and the corrected guidance signal Szc is output. That is, the guidance voice signal processing unit 30 performs compression processing based on the above-described masking tendency (b), and the level of the guidance voice signal from the second gain correction unit 32 increases as the value of the level detection signal LV increases. And the increase rate is automatically adjusted based on the frequency of the environment detection signal RC. Thereby, the guidance voice signal processing unit 30 adjusts so that the guidance voice reproduced based on the corrected guidance signal Szc is not masked by the reproduced music reproduced based on the corrected audio signal Sac. Yes.

  Then, the corrected guide signal Sac is amplified by a level adjusting amplifier 70 fixed at a predetermined amplification factor and supplied to the mixing unit 80.

  Next, the mixing unit 80 mixes the corrected audio signal Sac and the guide signal Szc, and supplies the mixed signal Sm to the speaker 400, thereby reproducing music or the like using the audio signal Sac and the guide voice using the guide signal Szc. Is played and output.

  According to the guidance voice mixing apparatus 10 of the present embodiment described above, the following effects can be obtained.

  That is, the audio signal processing unit 20 cuts the low frequency component of the audio signal Sa and further adjusts the level based on the level detection signal LV detected by the low frequency component detection unit 40. Can generate an audio signal Sac that has been corrected in accordance with a masking tendency that masks high-frequency sounds and high-frequency sounds are less likely to mask low-frequency sounds. Further, based on the environment detection signal RC generated by the listening environment detection unit 50, the low frequency component of the audio signal Sa is cut and further level adjustment is performed. Masking effect due to noise or the like can be reduced.

  Further, the guidance voice signal processing unit 30 extracts a frequency component from which the clearer guidance voice can be reproduced from the guidance signal Sz, and a low frequency component detection unit for the extracted frequency component of the guidance signal. Since the compression process is performed based on the level detection signal LV detected at 40, the guidance voice itself can be made easier to hear. That is, a frequency component that can be heard as a clearer guide voice in the audibility is allowed to pass through the guide voice signal Sz by a band pass filter or the like, and the amplification factor is increased when the level is small according to the level of the passed frequency component. Since the compression process is performed based on the level detection signal LV, the guidance voice itself can be made easier to hear.

  Further, since the compression processing is applied to the frequency component that enables the above-mentioned clear guidance voice to be reproduced based on the environment detection signal RC generated by the listening environment detection unit 50, only the masking effect by the reproduced music or the like is performed. In addition, the masking effect due to noise in the passenger compartment can be reduced.

  Further, the mixing unit 80 mixes (mixes) the audio signal Sac and the guidance signal Szc generated by the audio signal processing unit 20 and the guidance voice signal processing unit 30, and supplies the mixed signal Sm to the speaker 400 for reproduction. Therefore, it is possible to continuously output reproduced music or the like from the speaker 400 based on the audio signal Sac without distinguishing between when voice guidance is performed and when voice guidance is not performed. For this reason, it becomes possible to improve the problem that the driver and other passengers feel uncomfortable due to the discontinuation of the playback music or the like and the localization of the sound image fluctuating as in the prior art, which makes it feel uncomfortable. While listening to natural reproduction music and the like, it is possible to listen to the guidance voice clearly without being masked.

  1 has the configuration as the best mode for carrying out the invention, but in the case of a simpler configuration, the listening environment detection unit 50 or the guidance is provided. The audio signal processing unit 30 may be omitted, or the listening environment detection unit 50 and the guidance audio signal processing unit 30 may be omitted. That is, an audio signal that includes at least the audio signal processing unit 20 and that has been subjected to correction processing based on the level detection signal LV detected by the low frequency component detection unit 40, and the audio signal Sz output from the guidance audio signal generator 200. Is mixed by the mixing unit 80, and the speaker 400 is sounded based on the mixed signal Sm, so that the driver and passengers can hear the guidance voice clearly, and further reproduce music and the like. You can listen without feeling uncomfortable.

  Next, a guidance voice mixing apparatus according to a more specific embodiment will be described with reference to FIG. In the block diagram of FIG. 3, the same or corresponding parts as those in FIG.

  The configuration of the guidance voice mixing apparatus 10 of the present embodiment shown in FIG. 3 will be described in comparison with the embodiment shown in FIG. 1. A high-pass filter 21 corresponding to a first frequency correction section and a first gain correction section. The audio signal processing unit 20 having the attenuator 22 corresponding to the above and the low-frequency component detection unit 40 having the band-pass filter 40a and the level detection unit 40b are provided, and the guidance voice signal processing unit 30 is omitted. ing.

  The band-pass filter 40a has a frequency band (300 Hz not including direct current) lower than the lowest frequency fc (for example, 300 Hz) in the frequency band (for example, 300 Hz to 3.4 kHz) of the guidance voice reproduced based on the guidance voice signal Sz. Bandpass filter having a passband as a passband.

  The level detection unit 40b detects the level of the low frequency component of the audio signal Sa that has passed through the band pass filter 40a one by one, and supplies the level detection signal LV that is the detection result to the high pass filter 21 and the attenuator 22.

  As shown in the characteristic diagram of FIG. 2B, the high-pass filter 21 is formed of a high-pass filter that variably adjusts the cutoff frequency fa according to the value of the level detection signal LV. That is, the high-pass filter 21 has a characteristic of variably adjusting the cut-off frequency fa only by the value of the level detection signal LV regardless of the environment detection signal RC, and cuts and outputs the low frequency component of the audio signal Sa. To do.

  The attenuator 22 is formed of an electronic attenuator that adjusts the attenuation rate according to the value of the level detection signal LV with respect to the output of the high-pass filter 21. As shown in the characteristic diagram of FIG. As the value of the detection signal LV is larger, the attenuation rate is increased to output an audio signal Sac having a lower level. Further, the attenuator 22 adjusts the attenuation rate only by the value of the level detection signal LV, regardless of the environment detection signal RC.

  Then, the mixing unit 80 mixes (mixes) the audio signal Sac supplied via the amplification unit 60 and the guidance voice signal Sz supplied from the guidance voice signal generation device 200 via the amplification unit 70. The mixed signal Sm is generated and supplied to the speaker 400.

  According to the guidance voice mixing apparatus 10 of this embodiment having such a configuration, the high-pass filter 21 and the attenuator 22 cut the low frequency component of the audio signal Sa and further adjust the level based on the level detection signal LV. , “Low-frequency sound masks high-frequency sound, high-frequency sound is difficult to mask low-frequency sound” and “As the level of sound to be masked increases, the frequency range to be masked widens and the sound to be masked The audio signal Sac subjected to the correction according to the above-described masking tendency (a) and (b) can be generated. For this reason, the guidance voice output from the speaker 400 can be clarified based on the mixed signal Sm mixed in the mixing unit 80, and further, the voice audio signal Sac is not cut off during voice guidance. It is possible to improve the problem that the driver and other passengers feel uncomfortable due to the discontinuity of the sound and the like, and the localization position of the sound image changing.

  In this embodiment, the low-frequency component of the audio signal Sa is extracted by the band-pass filter 40a. However, it may be replaced with a low-pass filter having the above-described frequency fc as a cutoff frequency.

  Next, a guidance voice mixing apparatus according to another embodiment will be described with reference to FIG. In the block diagram of FIG. 4, the same or corresponding parts as those in FIG. 3 are denoted by the same reference numerals.

  The configuration of the guidance voice mixing apparatus 10 of the present embodiment shown in FIG. 4 will be described in comparison with the first embodiment shown in FIG. 3. The high-pass filter 21 provided in the audio signal processing unit 20 of the first embodiment Instead, a BASS processing unit 21a is provided, and the remaining configuration is the same.

  Here, as the BASS processing unit 21a, a BASS processing unit provided in the audio apparatus 100 such as a DVD player or a receiving apparatus is used to emphasize the low frequency component of the audio signal Sa. And the level detection part 40b reduces the enhancement amount of the low frequency component of the audio signal Sa in the BASS processing part 21a, so that the value of the level detection signal LV is large.

  Also with the guidance voice mixing apparatus 10 of this embodiment having such a configuration, the BASS processing unit 21a and the attenuator 22 reduce the low frequency component of the audio signal Sa based on the level detection signal LV to further adjust the level. Since the low frequency sound masks the high frequency sound, the high frequency sound is difficult to mask the low frequency sound. It is possible to generate an audio signal Sac that has been corrected according to the above-described masking tendency (a) and (b). For this reason, the guidance voice output from the speaker 400 can be clarified based on the mixed signal Sm mixed in the mixing section 80, and further, the voice audio signal Sac is not cut off during voice guidance, so that the reproduced music It is possible to improve the problem that the driver and other passengers feel uncomfortable due to the discontinuity of the sound and the like, and the localization position of the sound image changing.

  Next, a guidance voice mixing apparatus according to still another embodiment will be described with reference to FIG. In the block diagram of FIG. 5, the same or corresponding parts as those in FIGS. 3 and 4 are denoted by the same reference numerals.

  5 includes an audio signal processing unit 20 including a BASS processing unit 21a, a high-pass filter 21, and an attenuator 22, and the other configurations are the first and second embodiments. It is the same composition as.

  Also with the guidance voice mixing apparatus 10 of this embodiment having such a configuration, the BASS processing unit 21a adjusts the enhancement amount of the low frequency component of the audio signal Sa based on the level detection signal LV, and the high bass filter 21 Since the low frequency component of the audio signal whose amount of enhancement has been adjusted is cut, and the attenuator 22 adjusts the level of the audio signal from which the low frequency component has been cut, “the low frequency sound masks the high frequency sound, “High-frequency sounds are difficult to mask low-frequency sounds” and “When the masking sound level increases, the frequency range to be masked increases and the masking amount of the masking sound increases with respect to the masked sound”. The audio signal Sac subjected to the correction according to the masking tendency (a) (b) can be generated. For this reason, the guidance voice output from the speaker 400 can be clarified based on the mixed signal Sm mixed in the mixing unit 80, and further, the voice audio signal Sac is not cut off during voice guidance. It is possible to improve the problem that the driver and other passengers feel uncomfortable due to the discontinuity of the sound and the like, and the localization position of the sound image changing.

  Next, a guidance voice mixing apparatus of still another embodiment will be described with reference to FIG. In the block diagram of FIG. 6, the same or corresponding parts as those in FIGS. 1 and 3 are denoted by the same reference numerals.

  The guidance voice mixing apparatus 10 of the present embodiment shown in FIG. 6 has a configuration in which a guidance voice signal processing unit 30 is further provided in the guidance voice mixing apparatus of the first embodiment shown in FIG. The unit 30 includes a band-pass filter 31 corresponding to the second frequency correction unit and a compression processing unit 32 corresponding to the second gain correction unit.

  Then, the band pass filter 31 extracts a frequency component for reproducing a clearer guidance voice from the guidance voice signal Sz, and the compression processing unit 32 determines the level detection signal LV in FIG. By applying a compression process to the output of the bandpass filter 31 based on the same characteristics as shown in the characteristic diagram, the guidance voice itself can be made easier to hear. That is, the bandpass filter 31 passes the frequency component that can be heard as a clearer guidance voice in the guidance voice signal Sz, and increases the amplification factor when the level is small according to the level of the passed frequency component. Since the compression process is performed based on the level detection signal LV, the guidance voice itself can be made easier to hear.

  The guidance voice mixing apparatus 10 of this embodiment having such a configuration can also generate the audio signal Sac and the guidance voice signal Szc that have been corrected in accordance with the above-described masking tendency (a) and (b). The guidance voice output from the speaker 400 can be made clear based on the mixed signal Sm mixed in the unit 80. Furthermore, since the voice audio signal Sac is not cut off during voice guidance, the reproduced music or the like is interrupted. The problem that the driver and other passengers feel uncomfortable due to fluctuations in the localization position of the sound image can be improved.

  Next, a guidance voice mixing apparatus according to still another embodiment will be described with reference to FIG. In the block diagram of FIG. 7, the same or corresponding parts as those in FIGS. 4 and 6 are denoted by the same reference numerals.

  The guidance voice mixing apparatus 10 of the present embodiment shown in FIG. 7 includes the guidance voice signal processing unit 30 of the fourth embodiment shown in FIG. 6 in addition to the guidance voice mixing apparatus of the second embodiment shown in FIG. The guidance voice signal processing unit 30 includes a bandpass filter 31 corresponding to the second frequency correction unit and a compression processing unit 32 corresponding to the second gain correction unit.

  The guidance voice mixing apparatus 10 of this embodiment having such a configuration can also generate the audio signal Sac and the guidance voice signal Szc that have been corrected in accordance with the above-described masking tendency (a) and (b). The guidance voice output from the speaker 400 can be made clear based on the mixed signal Sm mixed in the unit 80. Furthermore, since the voice audio signal Sac is not cut off during voice guidance, the reproduced music or the like is interrupted. The problem that the driver and other passengers feel uncomfortable due to fluctuations in the localization position of the sound image can be improved.

  Further, by performing the effect described in the fourth embodiment, that is, the compression process, the guidance voice itself can be made easier to hear.

  Next, a guidance voice mixing apparatus according to still another embodiment will be described with reference to FIG. In the block diagram of FIG. 8, the same or corresponding parts as those in FIGS. 5 and 6 are denoted by the same reference numerals.

  The guidance voice mixing apparatus 10 of the present embodiment shown in FIG. 8 includes the guidance voice signal processing unit 30 of the fourth embodiment shown in FIG. 6 in addition to the guidance voice mixing apparatus of the third embodiment shown in FIG. The guidance voice signal processing unit 30 includes a bandpass filter 31 corresponding to the second frequency correction unit and a compression processing unit 32 corresponding to the second gain correction unit.

  The guidance voice mixing apparatus 10 of this embodiment having such a configuration can also generate the audio signal Sac and the guidance voice signal Szc that have been corrected in accordance with the above-described masking tendency (a) and (b). The guidance voice output from the speaker 400 can be made clear based on the mixed signal Sm mixed in the unit 80. Furthermore, since the voice audio signal Sac is not cut off during voice guidance, the reproduced music or the like is interrupted. The problem that the driver and other passengers feel uncomfortable due to fluctuations in the localization position of the sound image can be improved.

  Further, by performing the effect described in the fourth embodiment, that is, the compression process, the guidance voice itself can be made easier to hear.

  Next, a guidance voice mixing apparatus according to still another embodiment will be described with reference to FIG. In the block diagram of FIG. 9, the same or corresponding parts as those in FIGS. 1 and 8 are denoted by the same reference numerals.

  The guidance voice mixing apparatus 10 of the present embodiment shown in FIG. 9 is configured to further include the listening environment detection unit 50 of the embodiment shown in FIG. 1 in addition to the guidance voice mixing apparatus of the sixth embodiment shown in FIG. The BASS processing unit 21a, the high-pass filter 21 and the attenuator 22 included in the audio signal processing unit 20 are based on both the level detection signal LV and the environment detection signal RC, and the characteristics of the BASS processing and the cutoff frequency fc And the attenuation rate are automatically adjusted.

  Further, the compression processing unit 30b of the guidance voice signal processing unit 30 also has an amplification factor based on both the level detection signal LV and the environment detection signal RC as shown in the characteristic diagram of FIG. Adjust automatically.

  The listening environment detection unit 50 is formed by a look-up table or the like. As described in the description of the embodiment, the listening environment detection unit 50 evaluates the sensor signal Si from the sensor unit 300 according to a predetermined algorithm, Is generated and output.

  According to the guidance voice mixing apparatus 10 of the present embodiment having such a configuration, the same effects as those of the embodiment shown in FIG. 1 can be obtained.

  That is, the audio signal processing unit 20 cuts the low frequency component of the audio signal Sa and further adjusts the level based on the level detection signal LV detected by the low frequency component detection unit 40. Can generate an audio signal Sac that has been corrected in accordance with a masking tendency that masks high-frequency sounds and high-frequency sounds are less likely to mask low-frequency sounds. Further, based on the environment detection signal RC generated by the listening environment detection unit 50, the low frequency component of the audio signal Sa is cut and further level adjustment is performed. Masking effect due to noise or the like can be reduced.

  Further, the guidance voice signal processing unit 30 extracts a frequency component from which the clearer guidance voice can be reproduced from the guidance signal Sz, and a low frequency component detection unit for the extracted frequency component of the guidance signal. Since the compression process is performed based on the level detection signal LV detected at 4, the guidance voice itself can be made easier to hear. That is, the bandpass filter 31 passes the frequency component that can be heard as a clearer guidance voice in the guidance voice signal Sz, and the compression processing unit 32 reduces the level according to the level of the passed frequency component. The compression process is sometimes performed based on the level detection signal LV to increase the level by raising the amplification factor and lowering the level by lowering the amplification factor when the level is large, so that the guidance voice itself can be made easier to hear. it can.

  Further, since the compression processing is applied to the frequency component that enables the above-mentioned clear guidance voice to be reproduced based on the environment detection signal RC generated by the listening environment detection unit 50, only the masking effect by the reproduced music or the like is performed. In addition, the masking effect due to noise in the passenger compartment can be reduced.

  Further, the mixing unit 80 mixes (mixes) the audio signal Sac and the guidance signal Szc generated by the audio signal processing unit 20 and the guidance voice signal processing unit 30, and supplies the mixed signal Sm to the speaker 400 for reproduction. Therefore, it is possible to continuously output reproduced music or the like from the speaker 400 based on the audio signal Sac without distinguishing between when voice guidance is performed and when voice guidance is not performed. For this reason, it becomes possible to improve the problem that the driver and other passengers feel uncomfortable due to the discontinuation of the playback music or the like and the localization of the sound image fluctuating as in the prior art, which makes it feel uncomfortable. While listening to natural reproduction music and the like, it is possible to listen to the guidance voice clearly without being masked.

It is a block diagram showing the structure of the guidance audio | voice mixing apparatus which concerns on embodiment. It is a characteristic view for demonstrating the function of the guidance audio | voice mixing apparatus shown in FIG. It is a block diagram showing the structure of the guidance audio | voice mixing apparatus which concerns on Example 1. FIG. It is a block diagram showing the structure of the guidance audio | voice mixing apparatus which concerns on Example 2. FIG. It is the block diagram showing the structure of the guidance audio | voice mixing apparatus which concerns on Example 3. FIG. It is the block diagram showing the structure of the guidance audio | voice mixing apparatus which concerns on Example 4. FIG. It is the block diagram showing the structure of the guidance audio | voice mixing apparatus which concerns on Example 5. FIG. It is the block diagram showing the structure of the guidance audio | voice mixing apparatus which concerns on Example 6. FIG. It is the block diagram showing the structure of the guidance audio | voice mixing apparatus which concerns on Example 7. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Guidance voice mixing apparatus 20 ... Audio signal processing part 21 ... Frequency correction part, high-pass filter 21a ... BASS processing part 22 ... First gain correction part, attenuator 30 ... Guidance voice signal processing part 32 ... Second gain correction part , Compression processing unit 40 ... low-frequency component detection unit 40a ... band-pass filter (low-pass filter)
40b ... Level detection unit 50 ... Listening environment detection unit 60 ... Amplifier 70 ... Amplifier 80 ... Mixing unit

Claims (11)

A guidance voice mixing device that mixes a guidance voice signal and an audio signal and reproduces the mixed signal by a speaker,
Low-frequency component detection means for detecting the level of a predetermined low-frequency component of the audio signal;
The cut-off frequency is adjusted based on the detection result of the low-frequency component detection means to cut the low-frequency component of the audio signal, and the level of the audio signal from which the low-frequency component has been cut is determined by the low-frequency component detection means. Audio signal processing means for generating a corrected audio signal by attenuating according to the detection result;
Mixing means for mixing the guidance voice signal and the corrected audio signal;
A guide voice mixing apparatus comprising: Furthermore, a guidance voice signal processing means for performing compression processing on the guidance voice signal is provided,
Causing the mixing means to mix the correction audio signal with the guide signal subjected to compression processing by the guidance voice signal processing means;
The guidance voice mixing apparatus according to claim 1. Furthermore, a listening environment detecting means for detecting the listening environment based on a sensor signal detected by the sensor means is provided,
The audio signal processing means cuts the low frequency component of the audio signal by adjusting the cutoff frequency according to the detection result of the low frequency component detection means and the detection result of the listening environment detection means, and Attenuating the level of the audio signal from which low frequency components have been cut,
The guidance voice mixing apparatus according to claim 1. Furthermore, a listening environment detecting means for detecting the listening environment based on a sensor signal detected by the sensor means is provided,
The audio signal processing means cuts the low frequency component of the audio signal by adjusting the cutoff frequency according to the detection result of the low frequency component detection means and the detection result of the listening environment detection means, and The low frequency component is attenuated according to the level of the cut audio signal, and the guidance voice signal processing means is applied to the guidance signal according to the detection result of the low frequency component detection means and the detection result of the listening environment detection means. Applying the compression processing to
The guidance voice mixing apparatus according to claim 2. The audio signal processing means includes a high-pass filter that adjusts the cutoff frequency that is lower than the frequency band of the guidance voice signal, an attenuator that performs the attenuation process,
5. The guidance voice mixing device according to claim 1, wherein the guidance voice mixing device is provided. The low-frequency component detection means includes a band-pass filter or a low-pass filter that extracts the low-frequency component having a frequency lower than the frequency band of the guidance voice signal, and the level of the extracted low-frequency component. Level detecting means for detecting;
The guidance voice mixing apparatus according to claim 1, wherein the guidance voice mixing apparatus is provided.   The said audio signal processing means reduces the low frequency component of the said audio signal by a BASS processing means instead of adjusting the said cutoff frequency of the frequency lower than the frequency band of the said guidance voice signal. The guidance voice mixing device according to any one of -5. A guide voice mixing method of mixing a guide voice signal and an audio signal and reproducing the mixed signal by a speaker,
A low frequency component detection step of detecting a level of a predetermined low frequency component of the audio signal;
The cut-off frequency is adjusted based on the detection result detected in the low-frequency component detection step to cut the low-frequency component of the audio signal, and the level of the audio signal from which the low-frequency component is cut is set to the low-frequency component. An audio signal processing step of generating a corrected audio signal by attenuating according to the detection result detected in the detection step;
A mixing step of mixing the guidance voice signal and the corrected audio signal;
A guide voice mixing method comprising: Furthermore, a guidance voice signal processing step for performing compression processing on the guidance voice signal is provided,
In the mixing step, mixing the correction audio signal with the guide signal subjected to compression processing in the guidance voice signal processing step;
The guide voice mixing method according to claim 8. Furthermore, a listening environment detection step for detecting the listening environment based on a sensor signal detected by the sensor means is provided,
In the audio signal processing step, the cutoff frequency is adjusted according to the detection result detected in the low-frequency component detection step and the detection result detected in the listening environment detection step, so that the low-frequency component of the audio signal is adjusted. And attenuating the level of the audio signal from which the low frequency component is cut,
The guide voice mixing method according to claim 8. Furthermore, a listening environment detection step for detecting the listening environment based on a sensor signal detected by the sensor means is provided,
In the audio signal processing step, the cutoff frequency is adjusted according to the detection result detected in the low-frequency component detection step and the detection result detected in the listening environment detection step, so that the low-frequency component of the audio signal is adjusted. And attenuating the level of the audio signal from which the low frequency component is cut,
In the guidance voice signal processing step, according to the detection result detected in the low frequency component detection step and the detection result detected in the listening environment detection step, the compression signal is subjected to the compression processing,
The guide voice mixing method according to claim 9.

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